/**
 * 
 * 
 * 
 * Base64 encode / decode
 * 
 * http://www.webtoolkit.info/
 * 
 * 
 * 
 */

var Base64 = {

	// private property

	_keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",

	// public method for encoding

	encode : function(input) {

		var output = "";

		var chr1, chr2, chr3, enc1, enc2, enc3, enc4;

		var i = 0;

		input = Base64._utf8_encode(input);

		while (i < input.length) {

			chr1 = input.charCodeAt(i++);

			chr2 = input.charCodeAt(i++);

			chr3 = input.charCodeAt(i++);

			enc1 = chr1 >> 2;

			enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);

			enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);

			enc4 = chr3 & 63;

			if (isNaN(chr2)) {

				enc3 = enc4 = 64;

			} else if (isNaN(chr3)) {

				enc4 = 64;

			}

			output = output +

			this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +

			this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);

		}

		return output;

	},

	// public method for decoding

	decode : function(input) {

		var output = "";

		var chr1, chr2, chr3;

		var enc1, enc2, enc3, enc4;

		var i = 0;

		input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

		while (i < input.length) {

			enc1 = this._keyStr.indexOf(input.charAt(i++));

			enc2 = this._keyStr.indexOf(input.charAt(i++));

			enc3 = this._keyStr.indexOf(input.charAt(i++));

			enc4 = this._keyStr.indexOf(input.charAt(i++));

			chr1 = (enc1 << 2) | (enc2 >> 4);

			chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);

			chr3 = ((enc3 & 3) << 6) | enc4;

			output = output + String.fromCharCode(chr1);

			if (enc3 != 64) {

				output = output + String.fromCharCode(chr2);

			}

			if (enc4 != 64) {

				output = output + String.fromCharCode(chr3);

			}

		}

		output = Base64._utf8_decode(output);

		return output;

	},

	// private method for UTF-8 encoding

	_utf8_encode : function(string) {

		string = string.replace(/\r\n/g, "\n");

		var utftext = "";

		for (var n = 0; n < string.length; n++) {

			var c = string.charCodeAt(n);

			if (c < 128) {

				utftext += String.fromCharCode(c);

			}

			else if ((c > 127) && (c < 2048)) {

				utftext += String.fromCharCode((c >> 6) | 192);

				utftext += String.fromCharCode((c & 63) | 128);

			}

			else {

				utftext += String.fromCharCode((c >> 12) | 224);

				utftext += String.fromCharCode(((c >> 6) & 63) | 128);

				utftext += String.fromCharCode((c & 63) | 128);

			}

		}

		return utftext;

	},

	// private method for UTF-8 decoding

	_utf8_decode : function(utftext) {

		var string = "";

		var i = 0;

		var c = c1 = c2 = 0;

		while (i < utftext.length) {

			c = utftext.charCodeAt(i);

			if (c < 128) {

				string += String.fromCharCode(c);

				i++;

			}

			else if ((c > 191) && (c < 224)) {

				c2 = utftext.charCodeAt(i + 1);

				string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));

				i += 2;

			}

			else {

				c2 = utftext.charCodeAt(i + 1);

				c3 = utftext.charCodeAt(i + 2);

				string += String.fromCharCode(((c & 15) << 12)
						| ((c2 & 63) << 6) | (c3 & 63));

				i += 3;

			}

		}

		return string;

	}

}
